Medication delivery device

Abstract

A method of preventing setting a dose which exceeds an amount of medication contained in a medication receptacle of a medication delivery device. The device comprising a piston rod comprising a second stop element, a drive device for moving the piston rod, and a dose setting member for setting a dose. The method comprising the steps of moving a dose limiting member which comprises a first stop element axially with respect to the piston rod during dose setting, and utilizing the first and second stop elements to stop an axial movement of the dose limiting member in the proximal direction when the first and second stop elements catch, limiting a movement of the dose setting member for increasing a set dose of medication. The dose limiting member and the piston rod only interact directly, when the first and second stop elements catch.

What is claimed is: 
     
       1. A method of preventing a setting of a dose of medication which exceeds an amount of medication contained in a medication receptacle of a medication delivery device, the medication delivery device comprising
 a piston rod which is moveable in a distal direction for medication delivery, the piston rod comprising a second stop element, 
 a drive device for moving the piston rod in the distal direction for medication delivery, 
 a dose setting member for setting a dose of medication to be delivered, the method comprising the steps of
 moving a dose limiting member which comprises a first stop element axially in a proximal direction with respect to the piston rod during dose setting, and 
 utilizing the first and second stop elements to stop an axial movement of the dose limiting member in the proximal direction with respect to the piston rod when the first and second stop elements catch, 
 limiting a movement of the dose setting member for increasing a set dose of medication to be delivered, wherein the dose limiting member and the piston rod only interact directly, when the first and second stop elements catch. 
 
 
     
     
       2. The method of  claim 1 , further comprising the step of engaging the dose limiting member with the dose setting member. 
     
     
       3. The method of  claim 2 , further comprising the step of utilizing the dose limiting member to stop a movement of the dose setting member for increasing a set dose of medication to be delivered when the axial movement of the dose limiting member is stopped. 
     
     
       4. The method of  claim 1 , further comprising the step of coupling the dose limiting member to the dose setting member so that the dose limiting member is moved in the proximal direction with respect to a housing and with respect to the piston rod during dose setting when the set dose of medication to be delivered is increased by moving the dose setting member in a dose increasing direction. 
     
     
       5. The method of  claim 4  further comprising the step of coupling the dose limiting member to the dose setting member so that the dose limiting member is moved in the distal direction with respect to the housing during medication delivery. 
     
     
       6. The method of  claim 5 , further comprising the step of engaging the dose limiting member with an internal thread of the dose setting member. 
     
     
       7. The method of  claim 5  further comprising the step of engaging the dose limiting member with a threaded insert of the dose setting member. 
     
     
       8. The method of  claim 1 , further comprising the step of threadedly engaging a dose dial sleeve of the dose setting member with a housing and therefore allowing the dose dial sleeve to rotate and move proximally with respect to the housing during setting of a higher dose. 
     
     
       9. The method of  claim 8 , further comprising the steps of rotating and moving the dose dial sleeve distally with respect to the housing during a dose reducing step. 
     
     
       10. The method of  claim 9  further comprising the step of rotating and moving the dose dial sleeve distally with respect to the housing during a dose delivery step. 
     
     
       11. The method of  claim 1 , further comprising the step of threadedly engaging the dose limiting member with the dose setting member. 
     
     
       12. The method of  claim 1 , further comprising the step of threadedly engaging the dose limiting member with an insert of the dose setting member. 
     
     
       13. The method of  claim 1 , further comprising the step of extending the piston rod through an opening of the dose limiting member, wherein the first stop element is provided as a surface surrounding the opening. 
     
     
       14. The method of  claim 1 , wherein the first stop element comprises an abutment surface of an internal flange of the dose limiting member. 
     
     
       15. The method of  claim 1 , wherein the second stop element comprises a protrusion which extends radially from the piston rod, the axial position of the protrusion on the piston rod related to the total amount of medicament to be dispensed. 
     
     
       16. The method of  claim 1 , wherein the second stop element comprises the end of a thread on the piston rod. 
     
     
       17. The method of  claim 1 , wherein the piston rod comprises two threaded regions, a first threaded region which does not influence axial movement of the dose limiting member and a second threaded region, wherein one end of a thread in the second threaded region forms the second stop element. 
     
     
       18. The method of  claim 1 , further comprising the steps of allowing the dose limiting member to move axially and preventing the dose limiting member from rotating with respect to a housing. 
     
     
       19. The method of  claim 18 , further comprising the step of splining the dose limiting member to the housing, thereby preventing the dose limiting member from rotating with respect to the housing. 
     
     
       20. The method of  claim 1 , wherein the piston rod comprises two threaded regions.